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If Dinan does not sell the brackets.I am few weeks away from Mig Welding Vin new sway brackets on from Dinan,If some one checks with Dinan and they do not sell the brackets seperate with the suspension upgrade!We can ship them to Randy he could have a few sets made and sell them.If you want. p/s I think we better have a bottom Inspection this year at the gattering!

I'm wondering what the chances are of having bmw make a re designed diff cover with the dual mounts. and design another mount to be welded to the frame(someone posted another brand of cover on the fly)
I'm sure it will save them alot more by doing that then have another s54 episode on there hands,
My car is such low mileage that I haven't checked yet but I feel for the people that are having the problem

Funny my fellow HVAC Buddy,I just had that conversation with Andy about getting someone to make us the dual ear cover I also discussed drilling the bolts holding the cover on the Pside and adding stainless wire cables through the bolt to the frame to support the yaw of the difff,Trust me we all are chewing on this issue!!

Remember BMW has a histroy of the multi link suspensions ripping the body/subframe also.

The Z4 chassis is like no other before it, you need to do your homework

remember, the Z3 roadster chassis was terribly flimsy until they added the coupe roof structure, this made the chassis stiffer but never addressed weak link areas like the rear floorpan

The Z4 roadser chassis achieves almost the same stiffness numbers as the Z3 coupe, albeit sans roof structure, all the beef is in the lower chassis areas. Unlike the Z3 the Z4 diff mounts entirely to the tubular rear subframe assy. and the area where the subframe mounts is quite beefy and stiff. Don't see it happening myself

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Yesterday's history, tomorrow's a mystery, but today is a gift; that's why it's called the present

If Dinan does not sell the brackets.I am few weeks away from Mig Welding Vin new sway brackets on from Dinan,If some one checks with Dinan and they do not sell the brackets seperate with the suspension upgrade!We can ship them to Randy he could have a few sets made and sell them.If you want. p/s I think we better have a bottom Inspection this year at the gattering!

Clearly there is a fundamental problem but to what expent might something like a 3.46 or 3.73 conversion exacerbate the problem? It seems that the effective torque multiplication might hasten the problem given the ineffective mounting design.

Clearly there is a fundamental problem but to what expent might something like a 3.46 or 3.73 conversion exacerbate the problem? It seems that the effective torque multiplication might hasten the problem given the ineffective mounting design.

Randy, what are your thoughts on replacing the subframe bushings with Group N bushings? Do you thinkit would help in reducing subframe and diff movement. I ask because the bushings aint cheap and I don't think I could replace them myself, adding to the cost.

Although available for E30s and most E36s, I don't believe that the Group N bushings are available for Z3/M Coupe/Roadster.

Z3/ M Coupe/Roadsters have the same rear subframe bushing as the E36 318 Ti. It is very similar to the E30 bushing, but a bit shorter.

As far as I've been able to determine, currently only RTRS makes an aftermarket bushing for our cars. (EDIT: subsequent to original post, learned that Powerflex DOES NOT make a bushing for this application). However, the RTRS bushing appears to be modeled on the stock bushing. Though much stiffer urethane, it may not prevent the vertical movement (aka "slop").

Ireland Engineering also has a bushing listed on-line (under E30 Suspension). It appears very promising, but is not yet in production.

The Z4 chassis is like no other before it, you need to do your homework

remember, the Z3 roadster chassis was terribly flimsy until they added the coupe roof structure, this made the chassis stiffer but never addressed weak link areas like the rear floorpan

The Z4 roadser chassis achieves almost the same stiffness numbers as the Z3 coupe, albeit sans roof structure, all the beef is in the lower chassis areas. Unlike the Z3 the Z4 diff mounts entirely to the tubular rear subframe assy. and the area where the subframe mounts is quite beefy and stiff. Don't see it happening myself

I was thnking more of the E36 cars, requiring front and rear subframe reinformcents and rear sway bar mount reinforcements.

And as far as anyone can tell, the problem is NOT the stiffness of the car, but the fact that the subframe is very loose on the bushings.

In fact, being very stiff can cause more cracking, that's why airplane wings flex.

Although available for E30s and most E36s, I don't believe that the Group N bushings are available for Z3/M Coupe/Roadster.

Z3/ M Coupe/Roadsters have the same rear subframe bushing as the E36 318 Ti. It is very similar to the E30 bushing, but a bit shorter.

As far as I've been able to determine, both Powerflex and RTRS make bushings for our cars -- but they're both modeled on the stock bushing. Though much stiffer urethane, may not prevent the vertical movement (aka "slop").

Ireland Engineering also has a bushing listed on-line (under E30 Suspension). It appears very promising, but is not yet in production.

Neil

So we are back to Randy's bushing inserts.

But he was having problems making them.

And he keeps ignoring my suggestion for a way to make them easier, with s avery small change in effectivenesss. I may have to do it myself.

And he keeps ignoring my suggestion for a way to make them easier, with s avery small change in effectivenesss. I may have to do it myself.

Now Terry, you know you're too persistant to be ignored

I'll be honest though, I don't remember the specifics. Was your idea to pour them in situ? That was something else I had considered but did not linger on it (you could take up the airspace in the voids but couldn't eliminate the upper/lower gaps that allow the subframe to float).